Digital communicationDSL, GSM, CDMA, WCDMA, OFDM, WiMAX, Communication Algorithm, SDR, DSProcessor, encoders, decodersSun, 07 Jun 2020 07:14:32 +0000Sun, 07 Jun 2020 07:14:32 +0000Forum for Electronicshttps://www.edaboard.com/
Probability of error in the presence of Frequency offset in single carrier systemThu, 28 May 2020 16:34:15 +0000https://www.edaboard.com/threads/probability-of-error-in-the-presence-of-frequency-offset-in-single-carrier-system.390336/
https://www.edaboard.com/threads/probability-of-error-in-the-presence-of-frequency-offset-in-single-carrier-system.390336/invalid@example.com (rahul21apr)rahul21aprCan any help to simulate the Probability of error for BPSK in the presence of Frequency offset in single carrier system?
and also what is the theoretical BER in terms of frequency offset?

Thank you]]>0audio Bluetooth module connect to Bluetooth headsetWed, 13 May 2020 09:46:14 +0000https://www.edaboard.com/threads/audio-bluetooth-module-connect-to-bluetooth-headset.389954/
https://www.edaboard.com/threads/audio-bluetooth-module-connect-to-bluetooth-headset.389954/invalid@example.com (alibarghi)alibarghiI'm looking for two Bluetooth audio modules that can be connected.
all Bluetooth audio modules can be connected to a computer or mobile phone,
but I need a module to connect to a Bluetooth headset without using a computer or mobile phone.
Can anyone suggest me a module?]]>4USB and RS232 on the same connectorThu, 07 May 2020 09:17:56 +0000https://www.edaboard.com/threads/usb-and-rs232-on-the-same-connector.389950/
https://www.edaboard.com/threads/usb-and-rs232-on-the-same-connector.389950/invalid@example.com (subpilot)subpilotI have an a subsea scientific instrument that has an existing 5 pin connector that is currently being used for supply power 6 to 30 VDC and bidirectional RS232. I am upgrading the internal electronics of the instrument and want to be able to use the existing connector for Power/RS232 as well as a USB connection to Native USB port of a NRF52840 inside the bottle. I cannot change the connector or add more pins. It has to keep same connector and cannot just use USB solely. The idea being that...

USB and RS232 on the same connector]]>5ENC28J60 ARP request problemSat, 02 May 2020 06:29:33 +0000https://www.edaboard.com/threads/enc28j60-arp-request-problem.389851/
https://www.edaboard.com/threads/enc28j60-arp-request-problem.389851/invalid@example.com (RUKAEF)RUKAEFThis time I'm working with ENC28J60. I tried to obtain IP address using ARP request. Controller transmit packet correctly instead every 8th byte incrimented by one! What is the problem? Can anyone help me.

the the total power of 20mhz signal is 1W=30dbm, the power of a 1HZ bandwidth signal is 30-10log(20*10^6)= -43dbm. besides, the PAR of 256QAM ~ 7-> the peak power of a signal is -36dbm.
so, I just need a power amplifier which can stand only -36dbm (may be need some more back-off). Did I wrong ?]]>3Power Line Communication through Distribution Transformers?Mon, 17 Feb 2020 05:57:05 +0000https://www.edaboard.com/threads/power-line-communication-through-distribution-transformers.388796/
https://www.edaboard.com/threads/power-line-communication-through-distribution-transformers.388796/invalid@example.com (emaq)emaqIs it possible to have power line communication through several distribution transformer? The transceivers should be connected to 220V low voltage AC outlets with a communication link through a 11kV high-voltage line (delta-connected and without neutral) and through 11k/220V distribution transformers.

Are there any commercial products available to achieve the communication link or any DIY schematic to do this? The primary purpose of this communication is for the protection and fault...

Power Line Communication through Distribution Transformers?]]>0Digital modulation of radio transceivers into amateur use...Wed, 05 Feb 2020 08:59:31 +0000https://www.edaboard.com/threads/digital-modulation-of-radio-transceivers-into-amateur-use.388603/
https://www.edaboard.com/threads/digital-modulation-of-radio-transceivers-into-amateur-use.388603/invalid@example.com (Externet)ExternetGreetings.
Radio communications services for fire, police, ambulances and other institutions have migrated to digital modulation modes; which can be of several types from the little am aware. Can anyone provide/point a tutorial to all the methods beyond typical AM. CW, FM, SSB, FSK... in use these days ?

Of all those current digital voice modes, which are in use by the amateur radio groups ? What bands would they be usable or restricted ?
Old radio scanners are partially obsolete...

I am working on an addressable speaker system project on which some 25 speakers are connected, each with a PIC MCU inside and want to select one at a time. CAT6(8 wires) cables are connected. two pair for power 24VDC and 1 wire for communication. Maximum length around some 200mtrs. I am planning to send a unique PWM signal to select a specific speaker from master MCU. The PIC MCU inside, receive PWM...

Addressable speaker system]]>15MAX232 alternative with more lines in single packageThu, 23 Jan 2020 11:40:49 +0000https://www.edaboard.com/threads/max232-alternative-with-more-lines-in-single-package.388461/
https://www.edaboard.com/threads/max232-alternative-with-more-lines-in-single-package.388461/invalid@example.com (harvie)harvieHello, i am working on FPGA project with 32 duplex serial lines and i need to do conversion to RS232 voltage levels.
MAX232 can handle 4 lines, which would mean to use 16 pieces of MAX232 IC (only rx+tx, no hw flow control).
I wonder if there is similar IC which can do more lines in single package... i think it would makes sense to have at least 12 or 16 lines per IC...

I'm working on a design that draws power through USB but needs about 1.5A of current at 5V. Hence I'm exceeding the 500mA limit and need to "negotiate" a higher current from the source. I've read various pieces of USB documentation and I understand a small microcontroller would be the way to do this properly. I'm looking for a solution that doesn't require me to implement custom embedded software, however.

Does anyone know of any custom ICs that negotiate a higher current with the...

USB current negotiation]]>5MATLAB code of Bit Error Rate of UWB transceiverSat, 28 Dec 2019 18:52:52 +0000https://www.edaboard.com/threads/matlab-code-of-bit-error-rate-of-uwb-transceiver.388170/
https://www.edaboard.com/threads/matlab-code-of-bit-error-rate-of-uwb-transceiver.388170/invalid@example.com (hanen88)hanen88Hi
I would like to display the BER of Ultra wideband transceiver. Taking account that i designed this transceiver in ADS then i extract its output signal with the extension .csv. I put this output file.csv in the same location of file.m then i would like to calculate its BER. I'm so gratefull if you can give me a clear tutorial to display BER;

the following statement is taken from the telemetry standard IRIG Standard 106-11:

The RF signal is typically generated by filtering the baseband non-return-to-zero-level (NRZ-L) signal and then frequency modulating a voltage-controlled oscillator (VCO). The optimum peak deviation is 0.35 times the bit rate and a good choice for a premodulation filter is a multi-pole linear phase filter with bandwidth equal to 0.7 times the bit rate.

I've been experimenting with envelope analysis in Cadence and would like to plot the constellation and EVM for a QAM 16 modulated signal. I used the rectangular 16QAM block from rfLib in my testbench.

In SpecteRF wireless envelope analysis, there is the option of printing the constellation and EVM directly, but the wireless analysis option doesn't apply to my case because I'm not using any of the standard wprobes and wsources for LTE or WiFi. However, the classic envelope results do...

Consider a mobile wireless system, using QPSK modulation at 25 Ksymbols/s, and a carrier frequency of 1900 MHz. What is the fastest speed in km/h that is permissible for a vehicle using such system, if its required that the change in phase due to Doppler spread does not exceed 5 degree/ symbole?

]]>1Help Debugging Turbo Decoder Implementation in MatlabTue, 12 Nov 2019 01:43:48 +0000https://www.edaboard.com/threads/help-debugging-turbo-decoder-implementation-in-matlab.387574/
https://www.edaboard.com/threads/help-debugging-turbo-decoder-implementation-in-matlab.387574/invalid@example.com (bohulu)bohuluFor my research, i need to implement a Turbo Decoder to test a few things. I was able to write the BCJR algorithm code in MATLAB and for the most part, it works fine. By working fine, i mean that after a number of iterations, the number of errors reduces to zero or flatttens out. Where i am having a problem is that there are times where the number of errors randomly increases and decreases and that is affecting my results greatly. I was wondering if anyone has experienced this before and...

Help Debugging Turbo Decoder Implementation in Matlab]]>01200 baud data transfer over audio passband of cellphone. Is that possible?Thu, 31 Oct 2019 12:20:16 +0000https://www.edaboard.com/threads/1200-baud-data-transfer-over-audio-passband-of-cellphone-is-that-possible.387318/
https://www.edaboard.com/threads/1200-baud-data-transfer-over-audio-passband-of-cellphone-is-that-possible.387318/invalid@example.com (neazoi)neazoi1200 baud data transfer over audio passband of cellphone. Is that possible through the use of their codecs? Has anyone actually tried it? There are videos about comms on 300 baud but how about 1200 baud, has anyone ever tried it?]]>7Connect 32 serial lines to uC (eg. ESP32) over I2C or SPI?Tue, 29 Oct 2019 14:52:55 +0000https://www.edaboard.com/threads/connect-32-serial-lines-to-uc-eg-esp32-over-i2c-or-spi.387310/
https://www.edaboard.com/threads/connect-32-serial-lines-to-uc-eg-esp32-over-i2c-or-spi.387310/invalid@example.com (harvie)harvieHello,
i have approximately 32 Linux servers with 115200 baud serial console and i would like to connect all of them to single ESP32. While keeping things relatively scalable.
I know that first i have to convert the serial level to TTL using MAX232. Then i have to somehow manage all that lines.

Currently i am using raspberry PI with lots of USB serial converters and USB hubs, but it's kinda overkill, not very robust or reliable and far from being elegant. There are even solutions like...